Medical leads provide electrical stimulation from a medical device to a target site within a body of a patient. The medical device is typically implanted or otherwise installed on the body in an accessible area at some distance from the target site, and the medical lead is routed to the target site either through a percutaneous procedure or by surgical implantation depending upon the type and size of the medical lead being implanted.
An issue occurs when the patient is subjected to radiofrequency (RF) electromagnetic energy in excess of the ambient, such as when having a magnetic resonance imaging (MRI) scan. The metal filars within the lead have current induced by the RF energy. This induced current can produce heating within the medical lead and at the electrodes which can cause harm to the patient. A shield may be included within the lead to limit the amount of current induced on the filars and thereby reduce heating at the electrodes.
In some cases, multiple lead bodies may be paired. For instance, the multiple lead bodies may be positioned adjacently when implanted. One particular example of such positioning is for surgical leads that utilize two lead bodies to carry stimulation signals to a distal paddle. Both lead bodies may include identical braided conductive shields to limit the amount of heating. While the amount of heating at the electrodes may be reduced by the presence of the identical braided conductive shields, it may be desirable to reduce the amount of heating by an even greater amount to allow for even greater scan power levels.